Once again, you asked to show sums for each group after the whole list.What I'd require are extra totals per grouping based on a particular field of the data table, but at the end of the whole thing.
In this case, you should put another band and make necessary calculations there.
If you don't want to put another band in the report then the answer is no.
It's impossible to just change the position of the sums.
You should calculate them again.